[Limited evidence for negative pressure wound treatment of skin transplants and closed surgical wounds]. / Begrænset evidens for undertryksbehandling af hudtransplantater og lukkede kirurgiske sår--en gennemgang af et Cochranereview.

The indications for negative pressure wound treatment (NPWT) are increasing, e.g. for fixation of skin transplant and primary closed surgical wounds. The evidence for indications and positive effects are limited. NPWT should exclusively be used for fixation of split thickness skin transplants when immobilisation is otherwise difficult and for primary closed surgical wounds in selected patients at risk. Future high-quality investigations are necessary to pinpoint indications for topical negative pressure therapy, the effect of the different NPWT-modalities, and the overall economy compared to conventional bandages.

Second-harmonic generation of light at 544 and 272 nm from an ytterbium-doped distributed-feedback fiber laser.

We report external cavity second-harmonic generation of light at 544 and 272 nm based on an ytterbium-doped distributed-feedback fiber laser. The nonlinear crystal used to generate light at 544 nm is LiNbO3, and the maximum output of the cavity is 845 mW, corresponding to a conversion efficiency of 55%. In a second frequency-doubling step, using a beta-BaBa2O4 crystal, we generate up to 115 mW of light at 272 nm with a conversion efficiency of 14%.

Surgical treatment of pressure ulcers.

Although a pressure ulcer is a potentially serious condition that always calls for treatment, only a small percentage of patients with pressure ulcers are candidates for surgery. The choice between conservative treatment and surgery for a pressure ulcer depends on a thorough evaluation of the ulcer, as well as the patient's physical and mental states. In general, superficial pressure ulcers (stages I and II) are likely to benefit from conservative treatment. Deep pressure ulcers (stages III and IV, often resulting from spinal cord injury) often require surgical intervention. The surgical techniques described in this essay include direct closure (which is rarely indicated), local and sensate flaps, and skin grafting. Skin transplantation and cutaneous and other thin flaps have more limited indications in pressure ulcer surgery. Thorough debridement before reconstruction, patient compliance, control of concomitant disease, professional postoperative support, and sufficient pressure relief are imperative for treatment success.